Three wheeled scooter with rear skate truck and fixed front wheel

ABSTRACT

A scooter is disclosed which positions a center of gravity of a rider toward the front the scooter so that the rider can more easily perform a 180 degree turn trick. Since the rider is positioned closer to the front wheel, it becomes easier for the rider to flip over the handlebars. Fortunately, the scooter reduces a moment arm that defines a deceleration moment to reduce the likelihood that the rider will flip over the front handlebars.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation in part application of U.S. patentapplication Ser. No. 12/963,899, Filed Dec. 9, 2010, the entire contentsof which is expressly incorporated herein by reference.

STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT

Not Applicable

BACKGROUND

The present invention relates to a skateboard or scooter.

Prior art skate trucks are fabricated in the following manner. A hangerof the skate truck pivots about a nose. The hanger is biased to thestraight forward neutral position by an elastomeric member. However, theelastomeric member must be sufficiently rigid so that the rider's weightdoes not over power the bias force created by the elastomeric member.Additionally, the elastomeric member must be pre-tensioned to a specificamount to properly support the weight of the rider. These factors limitrotation of the hanger of the prior art skate truck to a narrow range.Moreover, there is a danger that the elastomeric member may bottom outas the rider progresses into a turn thereby inadvertently lifting theoutside wheels of the skate truck.

These prior art skate trucks are mounted to a deck of a skate board.Traditionally, one prior art skate truck is attached to each of theforward and rear portions in reverse fashion. When the deck of the skateboard is rolled to the left or right, the skate board is directed insuch direction. Unfortunately, the feeling experienced by the rider inturning the skate board is less than optimal.

Accordingly, there is a need in the art for an improved skate truck witha wide pivot range and a truck that can accommodate a wider weight rangeof riders and scooter with the skate truck.

BRIEF SUMMARY

The present invention addresses the needs discussed above, discussedbelow and those that are known in the art.

A stable skate truck that provides for a wide yaw angle and weight rangeof riders is provided. The skate truck has at least three (3) ballbearings that slide within grooves formed in one of either a base orhanger of the skate truck. The grooves match the ball bearings and havea ramp configuration to push the hanger away from the base as the skatetruck progresses into a turn. The ramps of the grooves may havedifferent profiles such as regressive, progressive, linear andcombinations thereof to provide the rider a different feel as the riderprogresses into a turn

A spring is preloaded and biases the hanger towards the base so that thetruck is normally in the straight forward direction. As the skate truckprogresses into a turn, the ball bearings slide within the grooves andthe spring is compressed to urge the ball bearings back to the center ofthe ramps and to urge the truck back to the straight forward direction.The spring assists in stabilizing the vehicle. A second component thatstabilizes the vehicle is the centrifugal force created as the riderprogresses into a turn. The centrifugal force applies a variabledownward force on a deck of the vehicle based on the turn radius. Thecentrifugal force is translated to the ball bearings and urges the ballbearing back to the center of the ramp further urging the truck back tothe straight forward direction. Another component that stabilizes thevehicle is the weight of the rider. The weight of the rider also urgesthe ball bearings back to the center of the ramp. Since the weight ofthe rider urges the ball bearings back to the center of the ramp, thepreload on the spring can be used for a wider weight range of riders.

More particularly, a suspension for a vehicle is disclosed. Thesuspension may comprise a base, a hanger and three ball bearings. Thebased may be mounted to a frame of the vehicle. The base may have threesemi-circularly shaped grooves within a first common plane. The threesemi-circularly shaped grooves may have a first center point. The threesemi-circularly shaped grooves may have a radius r. The threesemi-circularly shaped grooves may define a pivot axis perpendicular tothe first common plane and located at the first center point. The pivotaxis may be skewed with respect to a longitudinal axis of the frame ofthe vehicle.

Wheels may be mounted to the hanger so that the vehicle can roll on asurface. The hanger may have three mounting recesses within a secondcommon plane. The three mounting recesses may define a second centerpoint wherein a distance between the three mounting recesses and thesecond center point is r. The second common plane of the hanger may bedisposed parallel to the first common plane of the base. The secondcenter point may be positioned on the pivot axis.

The three ball bearings may be seated within the mounting recesses andtraversable along the three semi-circularly shaped grooves when thehanger rotates about the pivot axis.

The suspension may further comprise a biasing member for urging thefirst and second common planes closer to each other so that the ballbearings slide within the grooves as the hanger rotates about the pivotaxis. The biasing member may be a compression spring.

Each of the three semi-circularly shaped grooves may have a contactsurface which defines a ramp profile. The ball bearings may slideagainst the contact surface and compress or decompress the compressionspring as the ball bearings slide against the contact surface based onthe ramp profile. The ramp profiles of the three semi-circularly shapedgrooves may be identical to each other. The ramp profiles may beprogressive, regressive, linear or combinations thereof. Also, the threesemi-circularly shaped grooves may be symmetrically identical to eachother.

The suspension may further comprise a thrust bearing disposed betweenthe compression spring and the hanger to mitigate binding between thehanger and the spring as the hanger rotates about the pivot axis.

Moreover, a vehicle with the suspension system is disclosed. Inparticular, the vehicle may comprise a deck and a first suspensionsystem. The deck may define a front portion, a rear portion, a bottomsurface and a top surface.

The first suspension system may be mounted to the bottom surface at therear portion of the deck. The first suspension may comprise a base, ahanger, and three ball bearings. The base may be mounted to a frame ofthe vehicle. The base may have three semi-circularly shaped grooveswithin a first common plane. The three semi-circularly shaped groovesmay have a first center point. The three semi-circularly shaped groovesmay have a radius r1. The three semi-circularly shaped grooves maydefine a pivot axis perpendicular to the first common plane and locatedat the first center point. The pivot axis may be skewed with respect toa longitudinal axis of the deck.

The hanger may be used to mount wheels so that the vehicle can roll on asurface. The hanger may have three mounting recesses within a secondcommon plane. The three mounting recesses may define a second centerpoint wherein a distance between the three mounting recesses and thesecond center point is r1. The second common plane of the hanger may bedisposed parallel to the first common plane of the base. The secondcenter point may be positioned on the pivot axis.

The three ball bearings may be seated within the mounting recesses andtraversable along the three semi-circularly shaped grooves when thehanger rotates about the pivot axis.

The vehicle may further comprise a second suspension system mounted tothe bottom surface at the front portion of the deck. The first andsecond suspension systems may be mounted in opposite directions to eachother. The second suspension system may also comprise a base, a hangerand three ball bearings. The base may be mounted to a frame of thevehicle. The base may have three semi-circularly shaped grooves within afirst common plane. The three semi-circularly shaped grooves may have afirst center point. The three semi-circularly shaped grooves may have aradius r2. The three semi-circularly shaped grooves may define a pivotaxis perpendicular to the first common plane and located at the firstcenter point.

With respect to the second suspension system, the hanger may be used tomount wheels so that the vehicle can roll on a surface. The hanger mayhave three mounting recesses within a second common plane. The threemounting recesses may define a second center point wherein a distancebetween the three mounting recesses and the second center point is r2.The second common plane of the hanger may be disposed parallel to thefirst common plane of the base. The second center point may bepositioned on the pivot axis.

With respect to the second suspension system, the three ball bearingsmay be seated within the mounting recesses and traversable along thethree semi-circularly shaped grooves when the hanger rotates about thepivot axis.

Additionally, a three wheeled scooter is disclosed. The scooter maycomprise a deck, a fixed front wheel, a handlebar and a skate truck. Thedeck supports a rider. The deck defines a forward portion and a rearportion. The forward portion may be disposed at a lower elevationcompared to the rear portion. The fixed front wheel may be mounted to aforward portion of the deck. The handlebar may be mounted to the forwardportion of the deck. The skate truck may be mounted to the rear portion.The skate truck may be yawable to turn the scooter to the left or rightduring rolling of the deck.

The forward portion of the deck may define left and right outerportions. The left and right outer portions may be turned upward so thatthe deck can be rolled during tight turning of the scooter.

The front wheel has a rotational axis disposed above an upper surface ofthe front portion of the deck. The front wheel may be about 6 to 10times larger than rear wheels attached to the skate truck. For example,the front wheel may be a 20″ bicycle wheel.

A rotational axis of the rear wheels attached to the skate truck may bebelow the rotational axis of the front wheel. The deck may be closer tothe rotational axis of the rear wheels compared to the rotational axisof the front wheel.

The deck may have a slot for receiving the front wheel. A foot guard maybe disposed at a periphery of the slot. A flexible fender may bedisposed behind the front wheel for covering a rear side of the frontwheel.

A fork may be mounted to the forward portion of the deck. The frontwheel may be mounted to the fork. The handlebar may be mounted to acrown of the fork.

Moreover, a three wheeled scooter for transporting a rider is disclosed.The scooter may comprise a deck, a fixed front wheel, a handlebar and askate truck. The deck supports the rider. The deck may define a forwardportion and a rear portion. The deck may have a slot in the forwardportion of the deck. A longitudinal axis of the slot may be aligned to aforward direction of the scooter. The fixed front wheel may be mountedto a forward portion of the deck. The front wheel may be positioned atleast partially within slot so that a rider of the scooter can positionhis/her feet closely adjacent to the front wheel. The handlebar may bemounted to the forward portion of the deck. The skate truck may bemounted to the rear portion. The skate truck is yawable to turn thescooter to the left or right during rolling of the deck.

The scooter may further comprise a foot guard disposed at an innerperiphery of the elongate slot of the deck. The foot guard may extend upfrom the deck so that feet of the rider does not rub against the frontwheel when the rider is standing closer to the front wheel than the rearwheels.

The scooter may further comprise a front wheel guard disposed behind thefront wheel for protecting legs of the rider during riding wherein thefront wheel guard is sufficiently flexible so that the front wheel guardbends and contacts the front wheel when legs of the rider inadvertentlypushes against the front wheel guard to make a noise and warn the riderof danger.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the various embodimentsdisclosed herein will be better understood with respect to the followingdescription and drawings, in which like numbers refer to like partsthroughout, and in which:

FIG. 1 is a bottom view of a skate truck;

FIG. 2 is a cross sectional view of the skate truck shown in FIG. 1;

FIG. 2A is an illustration of a skateboard with skate trucks shown inFIG. 1 mounted to front and rear of a deck;

FIG. 3 is an exploded bottom view of the skate truck shown in FIG. 1;

FIG. 4 is an exploded view of a base and hanger shown in FIG. 3illustrating the assembly of the sliding bearings into grooves andmounting recesses;

FIG. 4A is an exploded view of a base and hanger illustrating a reverseembodiment shown in FIG. 4;

FIG. 5A is a graph illustrating spring force/ramp profile as a functionof degree of rotation of the hanger illustrating a first ramp profile;

FIG. 5B is a graph illustrating spring force/ramp profile as a functionof degree of rotation of the hanger illustrating a second ramp profile;

FIG. 5C is a graph illustrating spring force/ramp profile as a functionof degree of rotation of the hanger illustrating a third ramp profile;

FIG. 5D is a graph illustrating spring force/ramp profile as a functionof degree of rotation of the hanger illustrating a fourth ramp profile;

FIG. 5E is a graph illustrating spring force/ramp profile as a functionof degree of rotation of the hanger illustrating a fifth ramp profile;and

FIG. 5F is a graph illustrating spring force/ramp profile as a functionof degree of rotation of the hanger illustrating a sixth ramp profile.

FIG. 6 is a perspective view of a three wheeled scooter with rear skatetruck and fixed front wheel;

FIG. 7 is a side view of the scooter shown in FIG. 6;

FIG. 7A is a top view of the scooter show in FIG. 7 wherein the scooteris swung 180° about a contact patch;

FIG. 8 is a front view of the scooter shown in FIG. 6;

FIG. 9 is a top view of the deck and skate truck shown in FIG. 6;

FIG. 10 is an exploded perspective view of the deck and foot guard/frontfork shown in FIG. 6; and

FIG. 11 is an exploded perspective view of a handle bar and front wheelshown in FIG. 6.

DETAILED DESCRIPTION

Referring now to the drawings, a skate truck 10 is shown. The skatetruck may be mounted to a bottom surface 12 of a deck 14 of a scooter,skateboard or like vehicle 16 (See FIGS. 2, 2A and 6). When the deck 14is rotated about its central longitudinal axis 18 (see FIG. 2), a hanger20 may be yawed about a pivot axis 22 (See FIG. 3) to turn the vehicleleft or right. The pivot axis 22 is defined by three semi-circularlyshaped grooves 24 a-c and three bearings 26 a-c that slide within thegrooves 24 a-c (see FIG. 4) as the hanger 20 rotates about the pivotaxis 22. The bearings 26 a-c are seated within mounting recesses 28 a-c.The grooves 24 a-c may have a ramp profile. The ramp profile may haveleft and right sides 29 a, b (see FIG. 4) which are identical to eachother so that as the rider turns left or right, the response of theskate truck 10 is identical on the left and right sides 29 a, b. Foreach of the sides of the ramp profile, the ramp may push the ballbearings 26 a-c further away out of the groove 24 a-c as the riderprogresses in the turn. This pushes the hanger 20 further away from thebase 30. As the hanger 20 is pushed further away from the base 30,spring 32 is compressed to increase a spring force and stabilize thevehicle by biasing the vehicle 16/truck 20 back to the straight forwarddirection.

Three components urge the hanger 20 back to its normal straight-forwardposition to stabilize the vehicle during turns and straight-forwardmotion. In particular, the spring force of the spring 32 urges the ballbearings 26 a-c back to a center 31 of the ramp of the grooves 24 a-c.Additionally, the weight of the rider urges the ball bearings 26 a-cback to the middle or lowest portion 31 of the ramp defined by thegroove 24 a-c to dynamically account for the weight of the rider. Thethird component is related to the centrifugal force created duringturning of the vehicle 16. When the rider turns, the centrifugal forceapplies a variable downward force based on the turn radius onto the deck14 of the vehicle 16. This downward force also urges the ball bearings26 a-c back to the center 31 of the ramp of the grooves 24 a-c.

The hanger 20 is supported by the bearings 26 a-c and thrust bearing 34and does not directly contact the base 30 or the spring 32. Accordingly,the rotation of the hanger 20 does not cause the hanger 20 to rubagainst the spring 32 or the base 30. The hanger does not bind againstthe base 30 and the spring 32 as the hanger 20 rotates about the pivotaxis 22. As such, turning of the vehicle is smooth and effortless.

Accordingly, the skate truck 10 disclosed herein provides for a stableplatform which stabilizes the vehicle 16 toward the straight-forwarddirection and also dynamically accounts for the weight of the rider andthe turning motion to further urge the skate truck 10 back to its normalstraight-forward direction. Moreover, the hanger 20 rotates about pivotaxis 22 and is disposed between two sets of bearings, namely, thesliding bearings 26 a-c and the thrust bearings 34 so as to minimizefriction, mitigate binding and promote smooth turning of the vehicle 16.

More particularly, referring now to FIG. 1, the skate truck 10 includesthe hanger 20 which is supported on both sides by thrust bearing 34(e.g., needle thrust bearing) and sliding ball bearings 26 a-c (See FIG.3). When the hanger 20 rotates about the pivot axis 22, the thrustbearing 34 mitigates binding between the spring 32 and the hanger 20.Additionally, the ball bearings 26 a-c slide within grooves 24 a-c whichprevents contact between the hanger 20 and the base 30 to mitigatefriction between the hanger 20 and the base 30 as the hanger 20 rotatesabout the pivot axis 22. Accordingly, the thrust bearing 34 and thesliding bearings 26 a-c mitigate friction and provide for effortlessrotation of the hanger 20.

Referring now to FIG. 2, the hanger 20 is biased toward the base 30 byway of spring 32. A retaining pin 36 and a spring retainer 40 locatesthe spring 32. Although a compression spring is shown for spring 32,other types of springs are also contemplated. The retaining pin 36 maybe threaded into the base 30 with threaded connection 38. The pin 36 mayhave a central axis which is aligned to the pivot axis 22. However, thepin 36 does not define the pivot axis 22 of the hanger 20. The pin 36merely holds the assembly together. The grooves 24 a-c (see FIG. 3)formed in the base 30 define the pivot axis 22. In support thereof, theball bearing 26 a-c remain fixed within the mounting recesses 28 a-c(see FIG. 4) of the hanger 20. The mounting recesses 28 a-c are allwithin a common plane. As the hanger 20 rotates about the pivot axis 22,all of the ball bearing 26 a-c contact the ramps of the grooves 24 a-cat the same position. The ball bearings 26 a-c move in unison with eachother. When the hanger 20 rotates about the pivot axis 22, the ballbearings 26 a-c ride up and down on the ramps of the grooves 24 a-c atthe same position. Since the ball bearings 26 a-c track the grooves 24a-c, the grooves 24 a-c define the pivot axis 22. The retaining pin 36merely holds the ball bearings 26 a-c, hanger 20, spring 32 and thespring retainer 40 together but does not determine the pivot axis 22 ofthe hanger 20. To further show that the retaining pin 36 merely holdsthe assembly together and does not define the pivot axis, a gap 42 (seeFIG. 2) is shown between the retaining pin 36 and the interior surface44 of a hole 46 (see FIG. 3) formed in the hanger 20. This illustratesthat the retaining pin 36 does not guide rotation of the hanger 20 butonly holds the assembly together eliminating friction between theretaining pin 36 and the hanger 20.

Referring still to FIG. 2, a medial surface 48 of the hanger 20 isgapped 50 away from the medial surface 52 of the base 30 to mitigaterubbing friction between the hanger 20 and the base 30. A nut 54 may bethreaded onto the retaining pin 36 to compress spring 32 and hold theassembly together. The nut 54 may be a self locking nut or the threadedconnection may be coated with a chemical thread locker to mitigateloosening due to vibration. The spring force of the spring 32 biasingthe hanger 20 toward the base 30 may be adjusted by screwing the nut 54further down the retaining pin 36 or up off of the retaining pin 36. Thenut 54 is adjusted to adjust the spring force of spring 32 to eitherstiffen or loosen the suspension provided by the skate truck 10. The nutadjustment is made to account for the weight of the rider. For heavierriders, the spring 32 is proloaded to a greater amount compared to alighter rider. Regardless, since the weight of the rider also biases thetruck to the straight forward direction, the spring preload for aparticular rider can be used for a greater range of rider weights.

Referring now to FIGS. 5A-F, a spring force of the spring 32 as afunction of degree of rotation of the hanger 20 is shown. Only one sideof the ramp is shown in FIGS. 5A-F. In particular, positive rotation ofhanger 20 from the straight forward direction. The other side of theramp (i.e., negative rotation) is identical to the side shown in FIGS.5A-F but not shown for purposes of clarity. The graphs in FIGS. 5A-Frepresent various potential ramp profiles of the grooves 24 a-c. At zerodegree rotation of the hanger 20, the vehicle 16 is goingstraight-forward. For each degree of rotation, the ramps of the grooves24 a-c urge the ball bearing 26 a-c up the ramp. As the ball bearings 26a-c are urged up the ramp, the ball bearing 26 a-c push the hanger 20away from the base 30 and the spring is deflected. Typically, totaldeflection or lift is about 0.200 inches. As the spring is deflected,the spring force increases linearly as the spring is deflected withinits elastic range. The graphs (see FIG. 5A-F) show the spring force as afunction of degree of rotation of the hanger 20 which correlates to theramp profile of the grooves 24 a-c. As discussed above, the spring forceof the spring 32 helps in stabilizing the vehicle 16 to bring the hanger20 back to the straight-forward direction. As can be seen by the graphs,the spring force increases as the hanger 20 progresses into the turn.

FIG. 5A illustrates a linear ramp profile. For each degree of rotationof the hanger 20, the spring force is increased the same incrementalamount until the hanger is fully rotated and the spring force is at itsmaximum. In FIG. 5B, the ramp is initially linear during the firstportion 56 of the hanger rotation. During the second portion 58, foreach additional degree of rotation of the hanger 20, the spring forceincreases at a slower rate as shown by dash-line 60 which characterizesa regressive ramp profile. Alternatively, the ramp profile may beprogressive in that for each additional degree of rotation of the hanger20, the rate at which the spring force increases may accelerate as shownby dash-line 62. Referring now to FIGS. 5C and 5D, the first portion 56may be regressive as shown in FIG. 5C or progressive as shown in FIG.5D. The second portion 58 may be linear as shown by lines 64 or maycontinue on its regressive path 60 shown in FIG. 5C or may continue onits progressive path 62 as shown in FIG. 5D. FIG. 5E illustrates aprogressive ramp profile throughout the entire rotation of the hanger20. Oppositely, FIG. 5F illustrates a regressive ramp profile throughthe entire rotation of the hanger 20. Accordingly, the ramp profile uponwhich the ball bearings 26 a-c slide upon may have a linear profile,regressive profile, progressive profile or combinations thereof. Theramp profile can be customized to provide for a custom feel as the riderprogresses through a turn on the vehicle 16.

The skate truck 10 described above was shown as having three grooves 24a-c. However, it is also contemplated that more grooves 24 d-n may beincorporated into the skate truck 10. For example, the skate truck 10may have three or more gooves 24 a-n. These grooves 24 a-n should besymmetrically formed about a point so as to define the pivot axis 22 sothat the sliding bearings 26 a-c apply even pressure to the ramps of thegrooves 24 a-n. When three grooves 24 a-c are formed in the base 30, thegrooves 24 a-c can allow a +/− rotation of 60 degrees or less.Preferably, the grooves 24 a-c are formed so as to allow for a +/−rotation of about 50 degrees. When four grooves 24 are formed in thebase 30, the grooves 24 are formed to allow for rotation of the hanger20 to about +/−45 degrees or less.

Referring now to FIG. 4, the grooves 24 a, b, c can have a radius of r1.The center of the radius r1 defines the position of the pivot axis 22.Also, the mounting recesses 28 a, b, c can be positioned on a circlehaving a radius equal to r1.

As discussed above bearings 26 a-c are seated within the mountingrecesses 28 a-c. The bearings 26 a-c are also disposed within thegrooves 24 a-c. The bearings 26 a-c do not roll on the ramps defined bythe grooves 24 a-c. Rather, the bearings 26 a-c predominantly slide onthe ramp of the grooves 24 a-c. To facilitate sliding and not rolling ofthe bearings 26 a-c, grease can be disposed within the grooves 24 sothat the sliding bearings 26 a-c slides on the ramps defined by thegrooves 24 a-c. Babbitt material (e.g., zinc) may be coated on the rampsof the grooves 24 a-c and the bearings 26 a-c may be chrome finished toprotect the bearings 26 a-c and the ramps of the grooves 24 a-c from thepressure created between the bearings 26 a-c and the ramps of thegrooves 24 a-c

The grooves 24 a-c may have a semi-circularly shaped cross section andbe sized to fit the bearings 26 a-c so that the bearings 26 a-c contactsthe grooves 24 a-c along a line transverse to a curved length of thegroove. The contact surface (i.e., line) sweeps or slides along theramps of the grooves 24 a-c as the hanger 20 is rotated about the pivotaxis 22.

Referring still to FIG. 4, the spring 32 assists in pushing the bearings26 a-c to the lowest most portion 31 of the ramps defined by the grooves24 a-c. In other words, the spring 32 assists in biasing the hanger 20so that the vehicle goes in the straight forward direction. The weightof the rider also helps in urging the bearings 26 a-c down to the lowestmost portion of the ramps defined by the grooves 24 a-c. This too helpsin biasing the hanger so that the vehicle goes in the straight forwarddirection. A third component that helps in biasing the hanger so thatthe vehicle goes in the straight forward direction is the centrifugalforce created when the rider of the vehicle 16 makes a left or rightturn with the vehicle. As the rider progresses into a turn, acentrifugal force is created. The centrifugal force applies a force onthe deck 14 of the vehicle 16 based on a turn radius. This centrifugalforce is translated to the bearings 26 a-c to bias the bearings 26 a-ctoward the lowest most portion of the ramps defined by the grooves 24a-c.

The skate truck 10 can be mounted at the rear of the deck 14 in theorientation shown in FIG. 2. Arrow 66 shows the forward direction of thevehicle. As shown in FIG. 2A, the front of the deck 14 can also bemounted with a second skate truck 10 mounted in a reverse orientation tothe truck 10 shown in FIG. 2 so that rolling of the deck 14 turns thevehicle left or right. Other configurations are also contemplated. Forexample, the skate truck 10 can be mounted at the rear of the deck 14with a stationary or pivotable single or double front wheel with orwithout a handle bar. The skate truck can be mounted to the front of thedeck 14 with a stationary or pivotable single or double rear wheel. Ahandle bar can still be mounted to the front of the deck 14.

Referring now to FIG. 4A, the grooves 24 a-c may be formed in the hanger20 and the mounting recesses 28 a-c may be formed in the base 30.

Referring now to FIG. 6, the skate truck 10 may be attached to a rearportion 100 of deck 14. The base 30 of the truck may have four threadedholes that are aligned to countersunk holes formed in the rear portion100 of the deck 14. The skate truck 10 can be secured to the rearportion 100 of the deck 14 by way of screw 106 wherein the head of thescrews 106 is flush with the upper surface of the rear portion 100 ofthe deck 14. When the rider rolls the deck 14 about its longitudinalaxis 18, the hanger 20 and wheels 108 are yawed with respect to thelongitudinal axis 18. In particular, when the deck 14 is rolled indirection of arrow 110, the wheels 108 a, b move in direction of arrows112 a, b to direct the vehicle in the right direction. Conversely, whenthe deck 14 is rolled in direction of arrow 114, the hanger 20 and thewheels 108 a, b, rotate in the direction of arrows 116 a, b, to directthe vehicle 16 in the left direction. The front wheel 118 does not pivotto turn the vehicle 16. Rather, the front wheel is fixed and stationarywith respect to the deck 14. For purposes of turning, the rear portion100 of the deck 14 shifts to the left to effectuate a right turn orshifts to the right to effectuate a left turn due to the yawing actionof the hanger 20 and wheels 108 a, b. During the left and right turns ofthe vehicle 16, the vehicle 16 is turning about a contact patch 120directly below the rotational axis 122 of the front wheel 118. The rearportion 100 of the deck 14 pivots about the contact patch 120 toeffectuate the left and right turns of the vehicle 16. As shown in FIG.7, the contact patch 120 is directly below the rotational axis 122 ofthe front wheel 118. Due to the weight of the rider and the flexibilityof the front tire, the contact patch 120 is defined by an elongate area(see FIG. 7) of the front wheel 118 contacting the surface or ground andis not a point.

Referring now to FIG. 7, the deck 14 may have the raised rear portion100 and a lowered front portion 123 which lowers the center of gravityof the rider 200 and also reduces the likelihood of the rider flippingover the handlebars as discussed herein. The lower front portion 123 andthe raised rear portion 100 are joined to each other by an angledtransition portion 124. The transition portion 124 is angled so thatplacement of the rider's feet on the transition portion 124 will beuncomfortable and urges the rider to place his/her feet on the lowerfront portion 123 or as close to or under the rotational axis 122 of thefront 118, as shown in FIG. 7A, to position the rider on the deck mostoptimal for doing a 180° rotational (see FIG. 7A) trick on the scooter.The left and right feet of the rider are supported by the left and rightportions 126 a, b, (see FIG. 6). The deck 14 is sufficiently flexible toprovide cushioning due to vibration and impacts of uneven ridingsurface. The cushioning provides comfort to the rider in riding thevehicle 16.

Referring now to FIG. 8, the left and right portions 126 a, b are curvedupward at its outer peripheral edge 128 a, b. The curved left and rightportions 126 a, b allow the rider to achieve a tighter turn withouthaving the deck contact or grind against the ground. When the ridersteps on the left and right portions 126 a, b, the curved configurationthereof 126 a, b urges the knees 127 of the rider closer together abovethe front wheel guard 130. Also, the upwardly curved configuration ofthe left and right portions 126 a, b urges the feet of the rider closerto each other and against the foot guard 132. This position provides foran optimal riding stance. The wheel guard 130 prevents the user's legfrom rubbing against the front wheel 118 during riding. The foot guard132 prevents the feet of the rider from getting caught between the leftand right portions 126 a, b and the front wheel 118.

Referring back to FIG. 7, the front wheel 118 may be about six to tentimes larger than the rear wheels 108 a, b in diameter. The purpose ofthe larger front wheel 118 is to provide for lower rolling resistance aswell as a longer longitudinal tire patch 120 (see FIG. 7A) so that thefront wheel 118 can roll over gaps in the ground surface or rocks and/oruneven surfaces easier.

As discussed above, the deck 14 is shaped to position the rider's feetcloser to or under the rotational axis 122 of the front wheel 118. Thecenter of gravity 200 of the rider is preferably close to the rotationalaxis 122 of the front wheel 118 because this position allows the riderto more easily perform a 180 degree trick which is shown in FIG. 7A. Toaccomplish the 180° rotational trick with the scooter 16, the user orrider lifts the rear wheels 108 a, b off of the ground. The rider thenshifts his/her weight around the contact patch 120 of the front wheel118 to the ground. The rider swings around the contact patch 120. Thecontact patch 120 is located directly below the rotational axis 122 ofthe front wheel. An axis extending from the contact patch 120 defines arotational axis 216 (see FIGS. 7 and 7A) of the vehicle 16 during the180 degree trick. Since the rider's center of gravity 200 is close tothe contact patch 120, the centrifugal force which urges the rider offof the scooter is minimized since the distance 214 between the center ofgravity 200 and the contact patch 120 is minimized. The deck 14 wasformed to urge the rider's feet forward as discussed above. Accordingly,it is easier for the rider to perform the 180° turn or trick. If thedistance 214 between the center of gravity 200 of the rider and therotational axis 216 is large then it would be more difficult to performthe 180 degree trick since the centrifugal force when swinging aroundthe contact patch 120. would tend to urge the rider off of the vehicle16 and destabilize the rider's balance.

Unfortunately, when the center of gravity 200 of the rider is closer tothe rotational axis 122 of the front wheel 118, it is more likely thatthe rider will flip over the handlebars when the vehicle 16 rides over abumpy surface or hits a rock or some other obstacle. This is the reasonthat mountain bikers will shift their weight as far back as possiblewhen traversing down rocky terrain. In the vehicle discussed herein, thelarge front wheel 118 (e.g., 20 inch diameter) mitigates the rider fromflipping over the handlebars in a few different ways. The angle ofattack of the larger front wheel 118 is better than the angle of attackon a smaller wheel so that the front wheel is more likely to roll overthe rock or other obstacle instead of becoming stuck by the rock orother obstacle. Second, as the rider is riding forward, the generalprinciple is that the moment created by the weight 202 of the riderabout the rotational axis 122 must always be greater than anydeceleration moment. Otherwise, the rider will fly over the handlebars.The weight moment t of the rider is equal to the gravitational force 202multiplied by the distance 214 from the center of gravity 200 of therider to the rotational axis 122 of the front wheel. The decelerationmoment is equal to the deceleration force 206 created when the frontwheel 118 hits an obstacle multiplied by vertical distance 204 from thecenter of gravity 200 of the rider to the rotational axis 122. Ifdeceleration force 206 creates a greater moment about rotational axis122 compared to the weight 202 of the rider 16, then the rider will flipover the handlebars. If the front wheel 118 had a diameter equal to therear wheels 108 a, b as represented by dash lines 208, then the momentcreated by the deceleration force 206 would be increased proportionallyto the increased distance to the rotational axis 210 represented bydistance 212. Accordingly, the large front wheel 118 reduces thedeceleration moment by reducing the moment arm 204 to mitigate the riderfrom flipping over the handlebars. The lowered front portion 123 alsodrops the center of gravity 200 of the rider to reduce the moment arm204. The rider can position his/her center of gravity 200 closer to thecontact patch 120 and the rotational axis 122. The vehicle is designedto mitigate flipping over the handlebars by reducing the moment arm 204so that the rider is able to accomplish the 180° trick more easily.

Referring now to FIG. 9, the skate truck 10 including the wheels 108 a,b may have a width 134. The wheels 108 a, b are centered about thelongitudinal axis 18 and is spread apart as wide as possible to providea stable platform upon which the vehicle 16 and the rider are supportedbut not too wide to interfere with tight turning. The width 134 islimited by the rider's ability to push forward without hitting the wheel108 b with his/her foot 136. If the rider has a reverse stance then thewidth 134 of the wheels 108 a, b is limited to the extent that the otherfoot of the rider does not hit wheel 108 a as the rider is propellingthe vehicle forward 16 with his/her foot 136. The front wheel 118 may bepowered by a motor. In this instance, the width 134 is not limited bythe rider's ability to push forward without hitting the wheels 108 a, bwith his/her feet 136.

Referring now to FIG. 10, the deck 14 is secured to the frame 138 by wayof screws. In particular, the frame 138 may define the foot guard 132which circumscribes an inner peripheral of the left and right portions126 a, b of the deck 14. The bottom end 140 of the foot guard 132 hasflanges 142 on both sides of the foot guard that extend under the leftand right portions 126 a, b. The left flange in FIG. 10 is not visiblebut can be seen in FIG. 8. The left and right portions 126 a, b aresupported on top of the flanges 142. The flanges 142 may have one ormore raised nubs 144 having a threaded hole which receives screws 146.The left and right portions 126 a, b may have holes 148 that receive theraised nubs 144 and may also be countersunk to receive the screws 146and allow the head of the screws 146 to lay flush against the uppersurface of the left and right portions 126 a, b. Since the deck 14 restson top of the flanges 142, there is less opportunity for the screws 146to be stripped out of the threaded holes of the raised nubs 144. Theflanges 142 provide a secure and rigid support for the deck 14 and theweight of the rider.

Referring back to FIG. 8, the foot guard 132 is maintained as close tothe front wheel 118 as possible without rubbing against the front wheel118. To this end and also to accommodate the wider hub 150, the frame138 is skewed outward by angle sections 152 before the frame straightensout to parallel sections 154. The bend caused by the angle sections 152adds rigidity to the frame 138. Also, the selection of material for theframe 138 can be made to further rigidify the frame 138.

Referring to FIG. 10, forks 156 may extend from the parallel sections154. Forks 156 are joined to each other at crown section 158. The frontwheel 118, instead of being attached to the fork 156, may be attached tothe parallel section 154 (see FIGS. 8 and 11). The parallel sections 154may have slots 160 to receive the hub 150 of the front wheel 118. Thefront wheel 118 is secured to the parallel section 154 by way of nuts162 threaded onto the hub 150 as shown in FIG. 11.

As shown in FIGS. 7 and 11, the front wheel guard 130 may be mounted tothe crown 158 of the forks 156 and to a bracket 164 adjacent the footguard 132. In particular, the front wheel guard 130 may have two holesfor screws to attach the front wheel guard 130 to the bracket. The frontwheel guard 130 may additionally have a bracket 170 that allows thefront wheel guard 130 to be attached to the crown 158 by way of nut andbolt connection 172 a, b. The front wheel guard 130 when mounted isclosely adjacent to the front wheel 118. As the rider is riding thevehicle 16, the rider's leg may push into the front wheel guard 130. Thefront wheel guard 130 prevents the front wheel 118 from rubbing andburning the rider's leg. Instead, the front wheel guard 130 bends/flexesand rubs against the front wheel 118 and makes a loud noise to indicatethat the rider should move his/her leg to prevent the rubbing andburning of the front wheel guard 130 against the front wheel 118.

Referring to FIG. 10, a head tube 173 may extend up above the crown 158of the fork 156. The lower portion of the head tube 173 and the crown158 may have mating castellated configurations 174 and 176. Thecastellated configurations 174, 176 meet up to each other to preventrotation of the head tube 173 during the operation of the vehicle 16. Aclamp 178 circumscribes the castellated configuration 174, 176 of thehead tube 173 and crown 158 m and can be tightened by way of screws 180to rigidly secure the head tube 173 to the crown 158. Accordingly, thehead tube 173 may be removably attached to the crown 158 for thepurposes of disassembly for shipping and reassembly at a retail outletor a customer's home.

Referring now to FIG. 11, a handle bar 182 stem may be mounted to thehead tube 173 by inserting the head tube 173 into hole 184. Screws 186clamp the handlebar stem 182 to the head tube 173. A handlebar 188 maybe secured to the handlebar stem 182 by way of plate 190, which securesor is tighten onto the handlebar stem 182 by way of screws 192.Accordingly, the handlebar 188 is also removably attachable to the headtube 173 for the purposes of compact shipping as well as ease ofassembly after shipping. A cushion 196 can be wrapped around a crossbar198 of handle bar 188 to cushion a blow to the rider in the event of afall.

The head tube 173 may also be telescoping. It is contemplated that thehead tube 173 may have upper and lower tubes which collapse into eachother. The outer tube may have a compression lock which when engagedfixes the position of the inner tube to the outer tube. The purpose ofthe collapsible telescoping head tube 173 is for allowing the vehicle 16to be conveniently collapsed and folded for shipping.

The vehicle 16 may be disassembled and laid in a box for compactshipping from the manufacturing point to the retail point. Inparticular, the skate truck 10 may be removed from the deck 14. The deck14 may be removed from the frame 138. The handlebar 188 and the headtube 173 may be disassembled and laid into box 194 for shipment.

The vehicle 16 additionally has a front brake system (see FIG. 7). Thefront brake system 196 may have a brake lever 198 (see FIG. 11) whichoperates rim brakes 200 (see FIG. 11). Although a rim break is shown, adisk brake may also be mounted and operable by the front brake lever196.

Moreover, although the vehicle 16 is shown as being a foot poweredvehicle, it is also contemplated that a motor may be mounted to thefront wheel and powered by an electrical battery with throttle attachedto the right side of the handlebar 188.

The above description is given by way of example, and not limitation.Given the above disclosure, one skilled in the art could devisevariations that are within the scope and spirit of the inventiondisclosed herein, including various ways of mounting the truck to thedeck. Further, the various features of the embodiments disclosed hereincan be used alone, or in varying combinations with each other and arenot intended to be limited to the specific combination described herein.Thus, the scope of the claims is not to be limited by the illustratedembodiments.

What is claimed is:
 1. A suspension for a vehicle, the suspensioncomprising: a base mountable to a frame of the vehicle, the base havingat least three semi-circularly shaped grooves within first common plane,the at least three semi-circularly shaped grooves having a first centerpoint, the at least three semi-circularly shaped grooves defining apivot axis perpendicular to the first common plane and located at thefirst center point; a hanger for mounting wheels so that the vehicle canroll on a surface, the hanger having at least three mounting recesseswithin a second common plane, the at least three mounting recessesdefining a second center point, the second common plane of the hangerbeing disposed parallel to the first common plane of the base, thesecond center point positioned on the pivot axis; and at least threeball bearings seated within the mounting recesses and traversable alongthe at least three semi-circularly shaped grooves when the hangerrotates about the pivot axis.
 2. The suspension of claim 1 furthercomprising a biasing member for urging the first and second commonplanes closer to each other so that the hall bearings slide within thegrooves as the hanger rotates about the pivot axis.
 3. The suspension ofclaim 2 wherein the biasing member is a compression spring.
 4. Thesuspension of claim 3 wherein each of the: at least threesemi-circularly shaped grooves has a contact surface which defines aramp profile, the at least three ball bearings slide against the contactsurfaces and compress or decompress the compression spring as the atleast three ball bearings slide against the contact surfaces based onthe ramp profile.
 5. The suspension of claim 4 wherein the ramp profilesof the three semi-circularly shaped grooves are identical to each other,the ramp having a progressive profile, regressive profile, linearprofile or combinations thereof.
 6. The suspension of claim 3 furthercomprising a thrust bearing disposed between the compression spring andthe hanger to mitigate binding between the hanger and the spring as thehanger rotates about the pivot axis.
 7. The suspension of claim 1wherein the at least three semi-circularly shaped grooves aresymmetrically identical to each other.
 8. The suspension of claim 1wherein the pivot axis is skewed with respect to longitudinal axis ofthe frame of the vehicle.
 9. A vehicle comprising: a deck defining afront portion, a rear portion, a bottom surface and a top surface; afirst suspension system mounted to the bottom surface at the rearportion of the deck, the first suspension comprising a base mountable toa frame of the vehicle, the base having at least three semi-circularlyshaped grooves within a first common plane, the at least threesemi-circularly shaped grooves having a first center point, the at leastthree semi-circularly shaped grooves defining a pivot axis perpendicularto the first common plane and located at the first center point; ahanger for mounting wheels so that the vehicle can roll on a surface,the hanger having at least three mounting recesses within a secondcommon plane, the at least three mounting recesses defining a secondcenter point, the second common plane of the hanger being disposedparallel to the first common plane of the base, the second center pointpositioned on the pivot axis; and at least three ball bearings seatedwithin the mounting recesses and traversable along the at least threesemi-circularly shaped grooves when the hanger rotates about the pivotaxis.
 10. The vehicle of claim 9 wherein the pivot axis is skewed withrespect to a longitudinal axis of the deck.
 11. The vehicle of claim 9further comprising a second suspension system mounted to the bottomsurface at the front portion of the deck, the first and secondsuspension systems mounted in opposite directions to each other, thesecond suspension system comprising: a base mountable to a frame of thevehicle, the base having at least three semi-circularly shaped grooveswithin a first common plane, the at least throe semi-circularly shapedgrooves having a first center point, the at least three semi-circularlyshaped grooves defining a pivot axis perpendicular to the first commonplane and located at the first center point; a hanger for mountingwheels so that the vehicle can roll on a surface, the hanger having atleast three mounting recesses within a second common plane, the at leastthree mounting recesses defining a second center point, the secondcommon plane of the banger being disposed parallel to the first commonplane of the base, the second center point positioned on the pivot axis;and at least three ball bearings seated within the at least threemounting recesses and traversable along the at least threesemi-circularly shaped grooves when the hanger rotates about the pivotaxis.